Humin‐free synthesis of levulinic acid from fructose using heteropolyacid catalysts

Levulinic acid (LA) is one of the top bio‐based platform molecules that can be converted into many valuable chemicals. Herein, we report the sustainable synthesis of LA acid from various sugars using heteropolyacid catalysts. By using a Box–Behnken design of experiment, both LA yield (up to 69 mol%) and complete suppression of parasitic humin formation could be achieved within a 5 h reaction time at 140°C using fructose as a substrate. The effects of various reaction parameters like temperature, sugar concentration, addition of organic co‐solvent and reaction time on LA yield and humin formation were examined in a three‐dimensional space. Moreover, the results could be successfully transferred to other sugars like glucose or cellobiose, paving the way for an atom‐efficient and sustainable LA synthesis process.